Guys, it’s way to early to actually produce this light. It was predicted for 2018. To have it produced before 2019 would be to shatter reality as we know it.
I think the LH351D might be an awesome choice, actually. While those who want throw out of a small light might be disappointed, it doesn't seem to have the issues that the 219c and xpl hi have - The 219c would be pushed to run hotter and has less output, while the xpl hi would have low color quality and raise the price, with the maximum lumens perhaps 1/4 more than the 219c. The xp-g2 and xp-g3 have their own issues; the xp-g2 has the lowest output and the same low cri, and the xpg3 has poor beam consistency as far as tint goes although it gains more output in exchange for more heat. The LH351D however seems to be possessed of only one main trait that might not appeal to people, which is that it has a wide, smooth hotspot and not a tighter beam. I think that's fine personally; I will not be using this as any sort of thrower.
Maukka is very impressed by the LH351D's color quality in his /r/flashlight post on reddit "Samsung LH351D is a winner" especially on higher outputs. It is not plagued by tint shift across the beam, but it does rise above the BBL at low current (1x7135 or less, essentially) about as much as a 219c does. Its output is seemingly identical to the xp-g3's, and is much closer to the xpl hi than to the 219c. Should be about 9/10 as bright as the xpl on turbo; I doubt I could tell the output difference reliably. It'll be a nice floody beam with good color quality though. Maukka says that when using a mild minus green filter that lowered the color below the BBL, it took on a very nice quality of light comparable to a 219b sw40k, though of course with higher output.
Aircraft Kapton-insulated electrical wiring has been widely used in civil and military aircraft because it is lighter than other insulators and has good insulating and temperature characteristics. However, Kapton insulation ages poorly: an FAA study shows degradation in under 100 hours in a hot, humid environment, or in the presence of seawater. It was found to have very poor resistance to mechanical wear, mainly abrasion within cable harnesses due to aircraft movement. Many aircraft models have had to undergo extensive rewiring modifications—sometimes completely replacing all the Kapton-insulated wiring—because of short circuits caused by the faulty insulation. Kapton-wire degradation and chafing due to vibration and heat has been implicated in multiple crashes of both fixed wing and rotary wing aircraft, with loss of life.
Spacecraft
The descent stage of the Apollo Lunar Module, and the bottom of the ascent stage surrounding the ascent engine, were covered in blankets of aluminized Kapton foil to provide thermal insulation. During the return journey from the Moon, Apollo 11 astronaut Neil Armstrong commented that during the launch of the Lunar Module ascent stage, he could see “Kapton and other parts on the LM staging scattering all around the area for great distances.” [7]
According to a NASA internal report, space shuttle “wires were coated with an insulator known as Kapton that tended to break down over time, causing short circuits and, potentially, fires.”
I think you missed the point. Those people were saying they prefer the smooth Center section over a knurled center section. It didn’t have anything to do with the model of light.
My main concern with the LH351D is that it’s so floody. It would make the FW3A even more floody than a D4-219, and not useful at all for distance. My favorite option is XP-L HI, because it performs very well in general and gets closest to the beam type of an average EDC-style light.
FW3A LH351D: ~2 cd / lm? (Agro estimates ~1.5)
D4 219c: 3.2 cd / lm
D4 XP-G2: 4.1 cd / lm
D4 XP-L HI: 4.7 cd / lm
FW3A XP-L HI: ~4.5 cd / lm?
Common EDC lights: 5 to 10 cd / lm
And, as was hashed out at length in another thread, CRI is not always the top priority. I’m also not sure if Lumintop can actually get the LH351D. The poll determines what we ask Lumintop for, not necessarily what they’ll agree to.
Nichia 219c makes a nice beam, but it’s so hot… it might need 28-gauge wires or something to avoid damaging itself on turbo.
I really like xp-l HI also. They have great performance and efficiency. They have a nice clean beam when behind a carclo optic unlike the non HI variety. I expecially like something on or below the black body line like a 5A1 tint.